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Biomedical subjects

K V Golubtsov

Publications and source records attributed to K V Golubtsov.

12 recordsLinked to original sources
PubMed1989

[Intake of water and sodium chloride solution by the rats after central administration of litorin and immunization with litorin-bovine serum albumin conjugate].

Central injection of litorin suppressed water and sodium chloride solution intake, and also decreased the preference of saline of unrestrained rats during 1 hour test. Active immunization of animals with litorin-bovine serum albumin conjugate led to the augmentation of their daily saline preference. Immunized rats increased also avidity to salt after deprivation, though the consumption volume of liquids decreased. The data, obtained on the immunized animals prove the importance of definite level of endogenous bombesin-like peptide in the salt appetite of rats. The central effect of litorin is discussed in the aspect of changing by it the evaluation of gustatory information.

Animals↗
PubMed1977

[Membrane potential clamping in the horizontal cells of the fish retina].

The membrane potential of horizontal cells was clamped using uniform polarization of a layer of these cells by means of current passed via extracellular electrodes. It is shown that the voltage-current relationship of the nonsynaptic membrane of horizontal cells has in some cases sections with a negative slope. With fast shifts in the clamped potential level the changes in the membrane resistance are completed less than for 20 ms. Comparison of responses to light stimulation recorded with potential clamp and without it showed that participation of the nonsynaptic membrane in generation of responses to light stimulation can change significantly the form of the latter.

Animals↗
PubMedDate not supplied

[Study of the metabolic synapse. II. Comparison of the effects of cyclic 3',5'-AMP and 3',5'-GMP].

Intracellular microiontoforetic injections of cyclic 3',5'-AMP and cyclic 3',5'-GMP elicit different responses in the same neuron. Drugs were injected by current of 1--10 nA using 3-barrel micropipettes. Unlike cyclic 3',5'-AMP arising the depolarization of the neuron, cyclic 3',5'-GMP usually hyperpolarizes it. An inhibitor of phosphodiesterases, papaverine, increases and prolongates effects of cyclic 3',5'-AMP and cyclic 3',5'-GMP, but in latter case the action of this drug seems to be less.

Animals↗
PubMedDate not supplied

[Model of electrical feedback mechanisms through chemical synapses].

The model of excitatory chemical synapse is proposed in which the feed-back between the post- and presynaptic neurones is carried out by means of synaptic current generated by postsynaptic neurone. In the model, the potential drop generated by this current along the intercellular gap near the activated synapse (RIII) evokes additional depolarization of presynaptic membrane and thus stimulates the additional release of transmitter (fig. 1, A and B). The feed-back, which increases the steepness of transfer function between pre- and postsynaptic neurones is the more effective the higher the resistance of intercellular gap (fig. 2 and 3, B). is very low, so that activation of synapse is unable to change significantly its membrane potential (V2), the feed-back is the most effective, as revealed in additional depolarization of presynaptic membrane (VII in fig. 3, A). In inhibitory synapse the feed-back by electrical current is negative one.

Animals↗
PubMedDate not supplied

[Model of a neuron-regulator of the effectiveness of synaptic transmission].

In diad and triad synapses of vertebrate retina the transmitter released from one and the same presynaptic membrane can act simultaneously on two (or even three) postsynaptic neurones. The model of such a diad synapse is proposed, in which the positive electrical feed-back is caried out between one of postsynaptic and presynaptic neurones. The feed-back appears because of potential drop across the longitudinal resistance of intercellular gap (RIII) near the activated synapse (see [1]). It is shown that if the input resistance of this postsynaptic neurone (N3) is low (low R3 in fig. 1,), it can operate as a regulator of effectiveness of synaptic transmission between the presynaptic (N1) and the second postsynaptic (N2) neurones. The effectiveness of synpatic transmission (e. g. the steepness of transfer function) is the more, the higher the membrane potential in the neurone acting as a regulator (fig. 2), and the higher the resistance of intercellular gap (RIII) (fig. 2). The model reproduces the effect of polarization of horizontal cells (by means of light or current) on the membrane potential in bipolars of the turtle and fish retina (fig. 3). The analysis of the model also shows that one of the functions of horizontal cells, as regulators of synaptic transmission between photoreceptors and bipolars, may be the detection of small objects and borders of image against uniform background.

Models, Neurological↗
PubMedDate not supplied

[Methods of recording local ERG].

Two methods for recording the retinal local biopotential with the gaze fixation control and without this control are described, to be used for the assessment of the status of any retinal or macular site, among other things. A ring-shaped sucker electrode is employed in both methods; this electrode is supplied with a transparent anterior window and infrared-illuminated mirror in one method and in the other the electrode incorporates a light-emitting diode and an optic system that helps create a 6-20 degrees stimulus. Theoretical analysis and experimental findings evidence that the minimal area on the retina from which a local response may be obtained, fit for clinical purposes, conforms to 10-15 degrees with a stimulus 5 times brighter than semisaturating brightness. The local response share in this case is 70% and the number of possible blendings 50. The results explaining the choice of the conditions for the retinal local biopotential recording are presented. The suggested methods help assess the function of the macular area, distinguish between the functions of the cone and rod systems, record the total and Hanz-Feld electroretinograms without electrode substitution, record the macular biopotential in babies and in patients with nystagmus or with cataracts of various origins.

Cataract↗